Revolving screen



Nov. 13 1923?.

G. M. STEDMAN REVOLVING SCREEN Filed April 19; 1922 Patented Nov. 13, 1923.

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canons-in Ia. STEDMAN, or AURORA, INDIANA, nssIeNon TO S'IEDMANS FOUNDRY a MACHINE won-Ks, or apnoea, INDIANA, A CORPORATIO or INDIANA.

REVOLVING SCREEN.

Application filed April 19, was. Serial No. 555,552.

To all whom it may concern:

Be it known that I, GEORGE M. STEDMAN, a citizen of the United States, and residing at Aurora, in the county of Dearborn and State of Indiana, have invented a new and useful Improvement in Revolving Screens, of which the following specification is a full 'disclosure.

This invention relates to tapper mechanism construction and operation as applied to screening drums, of a type wherein the substance to be screened or sifted is placed, and the drum rotated to accomplish a sifting operation.

This invention relates to improved tapper mechanism construction and operation, and to the construction of the screen supporting frames forming when assembled the screening drum used in conjunction with said tapper mechanism. These drums are usually of hollow prismatic regular polygonal configuration, and, are formed of a series of spiders mounted immovably upon a shaft to which spiders, are attached frames, covered with wire screening of the desired mesh. Battles are generally, suitably arranged at the interior of the drums to cause the material to be raised and dropped upon the lower most faces of the screen walls. The adherence of the substance being screened, within the interstices of the screen material at the interior of the drum prevents the proper functioning of the screen, and much difiiculty has been experienced in thoroughly loosening the adhered substance thereform throughout the entire area of the screen walls.

An object therefore of the invention is to percussively vibrate the drum walls to loosen. the adhered substance, this object being furthered by successively tapping or striking and vibrating each wall throughout its entire area while the wall is in its uppermost or substantially horizontal position, the vibrative blows being delivered with predetermined frequency during each cycle of rotation of the drum. 7

Another object is the provision of screen frame units so constructed that each screen stretched thereacross will be thoroughly vibrated throughout its entire area when percussive blows are delivered indirectly thereagainst, by the improved adjustable tapper mechanism herein disclosed.

.. Another object isto vibrate each screen wall in its uppermost position, thus utilizing the action of gravity in conjunction with such vibration to thoroughly loosen the adhered substance throughout the entire screen area and cause it to fall to the lower side of the drum.

Another object is to provide means whereby the vibrative effects of the blows of the tapper arms will be positively transmitted to and throughout the entire area of the screen, although th blows may not be delivered at the exact center of a given screen, this object being accomplished by delivering the blows to metal strips aligned circumferentially in rotative planes, each strip being connected at its midpoint to a ridge-bar placed centrally and longitudinally of each screen and extending the. entire length thereof, the blows of the tapper arms being delivered to the metal strip and the vibrative effects carried or transmitted to the bars and then centrally distributed to the screen. Thus, when a tapper arm vibrates after its initial blow the arm will continue to strike some portion of the strips although the drum may have rotated, after such blow has been delivered. At whatever point, or points, the tappers may strike the strips the percussive effects will be transmitted and distributed centrally of and to the screen at which point the vibrative effects are most effective.

Another object is to provide for varying the intensity of the whip-like blows delivered by the tapper arms.

Another object is to simultaneously strike a plurality of strips upon a given drum wall by means of a corresponding number of tapper arms mounted upon a single shaft and operated automatically by and conformably to the rotation of the drum.

Other objects and certain advantages ap pear in a description of the drawings. for1n ing a part of this specification, and reference is made to said drawings, in which Figure 1 is a side elevation of one form of screening machine, the side walls of the same being broken away to show my improved screening drum formed of a plurality of screen frame units constructed in accordance with this invention and showing my improved tapper mechanism operable in conjunction therewith.

Figure 2 is an end view, partly in section,

illustrating-the improved screenframe (2011- 110 struction applied in the formation of a screening drum.

Figure 3 is a fragmentary end View of Fig. 1, showing in full and dot-and-dash lines the tapper-mechanism action and ad justment. l

The numeral 1 generally designates a type of machine technically known as a screen; comprising a suitably enclosed frame structure within which, and. mounted lengthwise thereof for rotation, is a drum 2 'Which, inthi's instance, com-prises screen Eachframeunit comprises two lar framesections of equala rea,a base s'ecframes yof improved. construction, oyer WlllCll framesis stretched the screening material 3 of any s'nit-ablemesh. I The drum is 7 supported longitudinallyof its central axis by a shaft l,slan't1ngly mounted n bearings 5- and 6, said bearings being carried upon ros's f-ralnesfi and S," and said shaft and drum being rotatable by'any suitable means indicated at 9. The substanceto be screened is introduced at the upperend, interiorly of the inclined drum through a hopper 10, a

' pe t-inner the substance passing through the screen and "th residue being discharged at rectangu tion 14 overwhich'th'e screening material 3 isinitially stretched and fastened,fand an outer clamping section 16 attachable to said base section overv the screening material. The sections are provided with centrally disposed longitudinal strips or bars, respeotively '17, 18, between which the'screen is also clamped when the frames are fastened toq'ether. The ridge-bar 1-8 is of greater depth than the bar 17 an'dextends outwardly, and beyond the planeof the outer section Elly-forming a ridge, crosswise of which are disposedyieldahle strips 20, hereind'enominated anvil-strips preferably of spring steel, fastened at their midqaortions to the ridge-bar 18' anchat their opposite ends to the parallel longitudinal members foo the fabric or any'bagg'ing of the same.

of the section 16. The ridge bar 18 is fas-v tened to the end railsof itsrfram'c and intermedi ately toliexible crossstrips 20 of arched form. The spring steel bowed strips hold the'barlS in suspension, and the bar in'turn holds the screen fabric to 'preyentinjury of A suitable n um berofsuch anvil strips are rovided, in this instance three; suitably spaced 7 apart throughout the length of each frame unit. The corresponding anvil-strips of all frame units when attached to the drum base, are circumferentially aligned in plane of rotation of the drum to insur the engagement of the tapper arms therewith. though the tapperiarms may first strike the strips directly overthe ridge-bars, since the drum continues its regular forward move- 'ment while the tapper arm continues to vibrategthe subsequent tappings of th arm may be at one sideor the other of theridge, and woulth but for my improved anvilstrins, strike directlyupon thescreen, causing injury thereto. parent, the effects of thetapper blows are As will be readily, ap-

herein distributed or transmitted bythe anvil-strips to ther-idge-bars, toflthe screens midway thereof, and 1 thence throughout their entire The tapper arms 20", one arm for each circumferential row of anvilstrips, arerigidly but adjustably-mounted upon ashaft 21, held in'suitable bearings 22 at one side oi and above the drum 2, and the shaft, and arms thereon, are operated simultaneously to give springing whip-like or percussive blows to the anvil strips 20 when any given drum face is in its uppermost position. V'llie tapper arm shaft 21 at one end and outside of the screenenclosure is provided with a 'triperm' 24rigidly1but adjustably mounted thereon, its outer end 25 being engageable with th stepped'te'eth 126 of tripwvheel 27 rigidly mountedupon the shaft i, the teeth of said wheel correspond ing'ito and being equal in'nuinber with the drum faces,"or of such a number as will act to control the periodicity and number of blows indirectly delivered against and at the uppermost surface of eithera poly-faced or cylindrical drum screen at each cycle of revolution thereof. jl he teeth are so related 'to the drum" faces that the trip-arm 24 will be raised and allowed to fall, (see Fig. 3) ,ximpa'i tiny; motion to'thetapper arms 20",

causing the same to give the snapping whiplilrc blows to the strips. 20, for percussiyely and uniformly agitating or vibrating the uppermost'drum wall-through means of the centrally disposed ridgegbar; to loosen the material adhering toits under inner surface. order to adjust the throw of thetapper arms to increase or decre'asel' lieir'force, and to vary'the qiutlity of tbeirwhipdilce ment and bumper means are provided, of which adescr'iption followsi V Attachedto thetrip arm 2% is a bumper 3O inthe form o'f a rubber dislg which bumper is designed tObont-act a headed screw 31 held'in a screw'threaded boss and adjustable therein, the boss forming an integral peof a; supporting arm attached to the side of the i'sereen frame.

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120 blows conformably to requirements; adjust lit) A set nut 34: is provided for holding screw 31 in its adjusted position. The screw adjustment is made (see Fig. 8, dot-and dash lines), so that the outer end of the rip arm in its lower position is slightly spaced from the trip wheel 27, and in this position the outer ends 20 of the tapper arms 20 are correspondingly slightly spaced above the anvil-strips and normally sustained in a non-strip bearing position. It has been found that the non-bearing sustension of the outer end of the arms 20 and 24: in relation respectively to the strips and trip-wheel prevents a backward snap of the arms after the strips have received their blows but allows the arms 20 to vibrate, generally giving a series of tapping blows during a short are of continued rotation of the drum. Inasmuch as the ends of the tapper arms are normally spaced from the anvil-strips 20 the arms in their arrested downward movement, are sprung or flexed to give the whip-like blows to the said strips.

To increase or decrease the percussive effects of the tapper arms blows, these arms are provided with weights 36 adjustable thereon toward and from the free end there of, which will vary the degree of vibration of the arms with respect to the anvil-strips conformably to an efficient cleansing of the screen.

The features herein claimed are of extreme importance and have been found to increase the output of the screen fifty per cent.

Having described my invention, I claim:

1. In a device of the class described, a foraminous wall drum composed of frame sections, each section comprising a pair of clamping frames, each frame having a centrally disposed longitudinal bar, said frames and bar adapted to engage at opposite sides of and clamp screen fabric therebetween, .each of the outer of said frames having a plurality of bowed strips disposed at a right angle to the outermost longitudinal bar, said strips attached to said. bar, bridging and spaced from said screening material, and terminally attached to Said frame, and arm. hingedly mounted and adapted to descend by gravity against any one of said cross strips.

2. in a device of the class described, a rotatable drum formed of a plurality of frame units having screening material clamped thereacross, each frame providing a centrally disposed longitudinal bar extending the full length thereof, and contac ing said screen material, a plurality of bowed strips disposed cross-wise of said bar attached thereto bridging said screening material and attached to said bar and frame, arms unitarily swingable for simultaneously striking all strips of each frame,

means for periodically raising said arms in a drum cycle, for descent by gravity to tap said strips, and bumper means for establisl1 ing a nonstrip bearing sustension of said arms, allowing arm vibration when said arms are tripped for percussively tapping said strips.

3. In. a device of the class described, a rotatable screening drum composed of a plu- .rality of frame units, each comprising a pair of frames, providing centrally dis posed longitudinal bars, screening material clamped between said frames and bars, one of said bars forming an outwardly directed ridge, a plurality of bowed strips bridging said screen, crossing said bar and attached to the bar at right angles thereto, and terminally fastened to opposite frame members, the corresponding strips of each frame being circum erentially aligned in planes of rotation of said drum, and means for simultaneously striking all strips of each frame when such frame is in its uppermost position.

4. In a device of the class described, a rotatable poly-faced drum, composed of frame units, each comprising a pair of rectangular sections designed to clamp screen fabric therebetween, a pair of centrally disposed longitudinal bars attached to each frame and extending the full length thereof, for clamping said screen therebetween, the outer of said bars forming a ridge across which and at right angles thereto are dis posed a plurality of strips bridging said screen fabric and attached at their outer e2;- tremities to the sides of said outer section, the corresponding strips of each frame be ing circumferentially aligned, means for simultaneously striking the strips of each frame when a given frame is in its uppermost position, said means descending by the action of gravity. and adjustable buffer means for establishing a nonstrip bearing sustension of said strip-striking means, to allow vibration of the same after striking said strips.

5. In a device of the class described, a drum providing a shaft for rotating the same, said drum formed of a plurality of frame units having screening material clamped thereacross. each frame providing a centrally disposed longitudinal bar contacting said screen material, a plurality of strips dis posed cross-wise of said bar attached there to and to said frame, corresponding strips of each bar being circumferentially alinged, when assembled to form the drum, arms unitarily swingable for simultaneously striking the strips of each frame, means for periodically tripping said arms in a drum cycle for descent by gravity, said meanscomprising a plurality of spring arms at tached to a rotatable shaft, a trip arm at the end of said shaft engageable with the teeth of a ratchet wheel on said drum shaft, and

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bumper means engageable With said trip arm and adjustable in relation thereto for establishing an arm nonstrip bearing sustension of said arms to allow Vvibrative movement of the same when tripped for percussively tapping said strips.

6. In a device of the class described, a frame for supporting a stretched screen fabric, a bar extending along the screen and secured at lts opposlte endsto sald frame,v

said bar adapted to be vibrated for jarring the screen fabric, a yielding member exr emme tended transversely to the bar and connected therewith and to the frame, foryieldingly sustaining saidbar, and'means for percussively tapping said bar. i V

In Witnes whereof, I hereunto subscribe my name, as attested by the two subscribing WltIIESSQS. V

GEO. M. STEDMAN.

Witnesses: I r CHESTER ADP EBLEs.

ROBT. B. Cass; 

